Starch

The purpose of this study is to identify the potential of starch as bio-based thermoplastic elastomers (TPEs). Starch based polymers have been recognized to have highly potential to replace existing source of conventional elastomeric polymers. The modification process of blending starch with natural rubber, plasticizers, additives, and filler contribute to the enhancement and improvement for the properties of starch in order to produce biopolymers by approaching the properties of TPEs. This research was based on the starch which is an abundant and naturally occurring polysaccharide. It used to prepare and evaluate edible biodegradable films of different starch sources namely potato starch, corn starch and oxidized corn starch. Biopolymers have been considered as the most promising materials for this purpose. Polymers that have recently attracted interest due to their highly modifiable material properties. Natural rubber obtained almost exclusively from the Para tree (Heveabrasilliensis) is a unique polymer in many significant applications. The use of plasticizers to process starch as thermoplastic polymer and the formulation of starch with other polymers are highlighted. Here we discuss the main results and developments innatural plasticizer/synthetic and biopolymer-based films.

The developments in the field of polymeric superabsorbent over the past decade are presented in the paper. Special attention has been paid to the preparation methods to emphasize the new synthesis strategies developed in the recent years.  Superabsorbent copolymers form as a result of the phase separation during the free radical cross linking copolymerization of sodium acrylate, methyl acrylate and methyl methacrylate monomers in the presence of inert diluents. It has been established that a variety of absorbent structures can be achieved during or after the cross linking by varying the independent parameters of the polymer synthesis, i.e. the degree of the polymer interactions, the amount of the cross linker and the diluents as well as the initiator concentration or the polymerization temperature. The most important reaction parameter to superabsorbent polymer synthesis is a ternary system composed of a polymer network, soluble polymers and low molecular compound. All concentrations of polymeric mass and properties of the monomers of the system change continuously during the cross linking process. Synthetic polymeric hydrogels represent a group of materials, used in various biomedical regulations, and are still developing for new promising applications.  There has been extensive development in the clinical and pharmacological precincts of hydrogels for drug delivery applications but imperative challenges remain. Here we also discuss the current movement in overcoming these challenges, specifically with regards to successfully delivering hydrogels inside the body without implantation, prolonging the release kinetics of drugs from hydrogels, and increasing the nature of drugs which can be delivered via hydrogel based approaches.  They have been effectively used as superabsorbent materials and in drug delivery, cell encapsulation and tissue repair due to their high water content and subsequent biocompatibility.

Marine Streptomyces sp.T1027 obtained from South coast of India was discovered to produce and accumulate β-carotene under the influence of light in liquid shake flask culture. The accumulation of β-carotene was growth associated and controlled by light, aeration, carbon and substrate solubility. Starch was the ideal substrate for maximum growth (4.5-6.1 g l-1) and β-carotene accumulation (92-130 μg g-1). Rapid extraction was done in Dimethylsulphoxide, Methanol (1:1) Solvent mixture. The organism was sensitive to a variety of antibiotics; in turn it was able to inhibit the human pathogen Corynebacterium diphtheria. Commercial substrates with high soluble starch content were found to produce maximum biomass and β-carotene production.